Transmission kick/jerk b/t 1st and 2nd under load

[petrosar]

Has anyone out there experienced a hard shift b/t 1st and 2nd when under 1/2 to 3/4 throttle load? This usually happens more often when the car is in the first 10 min of driving.

I have taken it to the dealer and they always come back with "unable to duplicate error". I even took a technician out once to test drive myself but the car didnt do it when he was with me.

Someone told me this is serious... another one said its a software upgrade for the TCU.

I just bought the car off my lease and its an 05 3.0 with 45k miles. Everything about the car is overall cherry but this is bothering me.

Any advice is greatly appreciated!